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July 30, 2007 -- A drug currently used to treat osteoporosis may also help
protect the bone and slow or perhaps even halt the progression of
osteoarthritis, according to early research.

A new study shows treatment with calcitonin, a hormone, effectively
prevented erosion of knee cartilage in rat models of osteoarthritis.
Osteoarthritis is also known as degenerative joint disease and is related to
cartilage breakdown in the joints which can lead to joint damage.

Calcitonin is currently used to treat Paget’s disease of the bone and
osteoporosis, as previous studies have shown that the hormone reduces bone
loss. But researchers say these results suggest that calcitonin may also help
prevent the joint destruction associated with osteoarthritis (OA).

New Option for OA

Osteoarthritis is the most common joint disorder and affects more than 10%
of Americans. Treatment usually addresses easing the pain caused by joint
stiffness and inflammation associated with osteoarthritis.

To date, no drug has been approved to prevent the gradual loss of cartilage
caused by the disease. But a new understanding of the progression of the
disease in recent years has prompted a surge of interest in developing
disease-modifying osteoarthritis drugs aimed at potentially preventing the
disease in those at risk, such as postmenopausal women.

In the study, published in Arthritis & Rheumatism, researchers
compared the effects of treating female rats that had their ovaries removed
with estrogen alone and estrogen plus calcitonin.

Loss of estrogen from age or other causes increases the risk of
osteoporosis. Other research has suggested that hormone replacement therapy
helps protect postmenopausal women from osteoarthritis. This study showed that
estrogen therapy and calcitonin given to rats helped reduce the rise in
compounds indicative of joint destruction of osteoarthritis.

Calcitonin and estrogen also worked effectively in protecting against
surface erosions of joint cartilage.

“Calcitonin treatment may counter the acceleration of cartilage degradation
and the related rise of surface erosions,” writes researcher Bodil-Cecilie
Sondergaard, of Nordic Bioscience Diagnostics in Herlev, Denmark, and
colleagues.

Researchers say these results are only preliminary, but they suggest that
calcitonin merits further research in human clinical trials.